In order to monitor water quality in mains supplies intended for consumption, i.e. drinking water, it is necessary to sample the water supply from time to time. Currently this is usually achieved by a technician visiting a hydrant, accessing the water supply and carrying out suitable tests with portable sampling equipment that is taken from job to job. Alternatively, the water main may be exposed by excavation and then drilled into and an insertion valve fitted, through which an instrument may be attached to the main. These methods are so time consuming and expensive as to make extensive monitoring impractical.
WO-A-2005/052573 discloses a sampling apparatus attachable to a hydrant (these provide extensive access to the mains distribution network) with an outlet configured to provide periodic flows of fluid through the apparatus. However, it is desirable to have a less complex apparatus and certain water quality sensors cannot function adequately in a periodic flow.